1. Field of the Invention
The present invention relates to a semiconductor device which allows characteristic adjustment to be performed after being packaged.
2. Description of the Related Art
Normally, a fuse made of poly-silicon is provided beforehand to a power source IC (Integrated Circuit), such as a voltage regulator or an AC/DC converter for performing characteristic adjustment of the IC. In order to fabricate an IC product (final IC product) having specifications requested by a user, a prefabricated IC wafer (an IC in a wafer state) has its characteristics measured after specifications of the IC product are decided and undergoes a trimming process in which a fuse provided to the IC wafer is suitably cut by a laser device based on the measured characteristics of the IC wafer. By performing the trimming process, characteristics of the IC such as output voltage are adjusted to match the specifications requested by the user (characteristic adjustment).
In the above method, since the characteristic adjustment is performed when the IC is in a wafer state, characteristics of the IC wafer may shift (characteristic shift) after the IC wafer is assembled as a package (packaging). In addition, since the IC fabrication operation using the above-described method requires performing a wafer test, a trimming process, a packaging process, and a final test, the IC fabrication operation becomes long. It is, therefore, desired to perform characteristic adjustment after the IC wafer is packaged.
Japanese Laid Open Patent Application No. 11-273373 discloses a non-volatile memory integrated circuit for storing analog signals along with retrieving the stored analog signals and reading out the retrieved analog signals.
Japanese Laid Open Patent Application No. 2007-028898 discloses a battery package which is safe, and seldom suffers from troubles of FET or breaking of the current fuse even when an ON-state resistance of a control FET becomes small.